On Thu, 5 Mar 2026 00:33:21 GMT, David Holmes <[email protected]> wrote:
>>> Do you have any more information on this security bug? >> >> I found following bug from mail thread. But I cannot access it due to >> security bug. >> >> https://mail.openjdk.org/pipermail/hotspot-runtime-dev/2011-August/002357.html >> >> 4852809: Linux: do not use alternate signal stack > >> > Do you have any more information on this security bug? >> >> I found following bug from mail thread. But I cannot access it due to >> security bug. >> >> https://mail.openjdk.org/pipermail/hotspot-runtime-dev/2011-August/002357.html >> >> 4852809: Linux: do not use alternate signal stack > > Actually I made this public last year: > https://bugs.openjdk.org/browse/JDK-4852809 > > There were two main issues: > 1. Newly created threads inheriting the same alt-stack as parent > 2. Issues with accessing TLS with Linux fixed-stack implementation > > I don't quite see how #1 could arise, and #2 is definitely not an issue any > more. Hi @dholmes-ora and @YaSuenag ! Sorry for the rebase; something messed up my branch and I had to rebase over master to get it clean again. Not sure what happened. Thank you both for your feedback; I was busy with other stuff, and this moved down the pile. I tried to address your concerns. hotspot Tier1 and Tier2 are currently running on my machine with the feature enabled. @dholmes-ora > My main concern with this is that it is so hard to test and we will never > know to what extent it is getting used. It's usefulness depends entirely on > support organizations knowing about it and telling customers to enable this > (in production - which they might balk at) to try and better diagnose mystery > crashes. That is true, unfortunately. Whether this is useful enough is a matter of taste, but I know I could have used it a bunch of times already, and there are an unknown number of JVM-just-vanishes cases that could turn out to be stack overflows. ------------- PR Comment: https://git.openjdk.org/jdk/pull/29559#issuecomment-4118872820
